A method for spectrum noise detection is provided. Means and a total mean of spectrum blocks of a frequency-domain signal are calculated. Whether the means are greater than a cut-off threshold is checked. If all the means are greater than the cut-off threshold, whether the means range between a variance lower bound and a variance upper bound is checked, an estimation bandwidth corresponding to the spectrum blocks is obtained according to a bandwidth check threshold, and whether a central frequency of the estimation bandwidth approximates a central frequency of the spectrum of the frequency-domain signal is checked. If the number of the means ranging between the variance lower bound and the variance upper bound exceeds a default value, and the estimation bandwidth is greater than a predetermined bandwidth and the central frequency of the estimation bandwidth approximates the central frequency, the frequency-domain signal is determined as a noise signal.